|Symbol|GSI|Meaning|Unicode|Description|
|---|---|---|---|---|
|◬|○|Base triangulation surveying point|U+25EC|Dot in upward-pointing triangle|
||○|Electronic triangulation point||Dot in upward-pointing triangle with flag|
|⊡|○|Benchmark|U+22A1|Dot in square|
|⛭|○|Factory|U+26ED|Gear without hub|
|⛯|○|Lighthouse|U+26EF|Map symbol for lighthouse|
|⛮|○|Power station|U+26EE|Gear with handles|
|文|○|Elementary or junior high school|U+6587|Kanji bun|
|㉆|○|High school||Kanji bun in a circle|
||○|University||Kanji bun with a smaller kanji 大 (for daigaku) in brackets on top|
||○|Technical college||Kanji bun with a smaller kanji 専 (for senmon gakkō) in brackets on top|
|〶|○|Post office|U+3036|Down tack (T-shape) with overbar in circle|
|〒|×|Sub post office (not distribution centre)|U+3012|Down tack (T-shape) with overbar|
|⭙|○|Police station|U+2B59|Heavy circled saltire|
|☓|○|Koban (police box)|U+2613|Diagonal cross (saltire)|
|⊕|○|Public health centre|U+2295|Greek cross in circle|
|⛨|○|Hospital||Greek cross in shield|
|⭖|○|Prefectural Office|U+26FB|Oval bullseye|
|⭗|○|City hall|U+2B57|Heavy circle with circle inside|
|◉|○|Ward office|U+25C9|Fisheye|
|⭘|○|Town hall|U+2B58|Heavy circle|
|⛩|○|Shinto shrine|U+26E9|Shinto shrine|
|卍|○|Buddhist temple|U+534D|Manji (Swastika)|
|⛫|○|Castle|U+26EB|Castle|
|⛼|○|Cemetery|U+26FC|Headstone graveyard symbol|
|♨|○|Onsen (hot springs)|U+2668|Oval with three vertical wavy lines|
|⛬|○|Historical landmark|U+26EC|Historic site|
|⛰|○|Summit|U+26F0|Mountain|

Question: how many symbols are not shown?
Answer: 3